4.2 Integrated Information Theory
Studying consciousness in non-human animals.
- While most non-human animals do not exhibit as much self-consciousness or depth of consciousness as humans, they are generally understood to be conscious. For instance, dogs exhibit behavioral cues that allows us to understand their conscious states.
- Samples of non-human mammalian cortical tissue all look very similar to that of humans and many have the same number of cortical layers. Indeed there is a great continuity in brain structure across mammalian animals; neuroscience has not found anything in particular about the human brain that makes it totally stand out from other species.
- Because non-human animals are conscious and have remarkably similar brains to ours, scientists can study consciousness in the lab using animals like mice and monkeys.
Modern neuroscientific techniques allow us to peer into the working minds of animals.
- Recent breakthroughs in molecular biology and genetic engineering have given neuroscientists unprecedented access into the biomechanics of living brains.
- For instance, an experiment at the Allen Institute for Brain Science in Seattle modified genes in mice to allow fluorescence of their neurons whenever they fired. This allowed them to watch the mouse’s brain activity in real time, providing a window into the cellular-level functions of an active brain.
- Optogenetics is another novel biological technique which uses light to control neurons that have been genetically modified to express light-sensitive ion channels. This allows neuroscientists to specifically, delicately, and transiently turn on or off specific nerve cells in the brain and observe the resulting change in consciousness.
Continued exploration of the problem of consciousness requires a way to identify and quantify the phenomenon.
- Scientists do not yet understand why specific regions like the cortex or thalamus give rise to consciousness while others do not.
- There is much yet to be explored about the origins and development of consciousness in individuals. The time at which consciousness first arises in the growth and development of humans in still unknown.
- Advancements in artificial intelligence have led to controversy on how and when we can decide if computers are experiencing consciousness. Many of the abilities exhibited by technologies such as SIRI, Deep Blue, and Watson would be considered to be the result of consciousness if exhibited by patients in a hospital.
- We need a theory that takes us from conscious experience to the underlying hardware in order to be able to identify and quantify consciousness.
Integrated information theory allows us to identify and measure consciousness.
- The theory, developed by Giulio Tononi, predicts whether a system is conscious, to what degree it is conscious, and what particular experience it is having. It does this based on five axioms: intrinsic experience, composition, information, integration, and exclusion.
- A conscious system is defined as any system that has a causal influence on itself. The more cause-effect power a system has on itself, the more it is conscious under this definition.
- IIT not only defines conscious systems but allows us to measure their level of consciousness, by measuring the degree of integration in the network. For example, the brain can be stimulated with transcranial magnetic stimulation. The resultant electrical reverberation can be measured via multichannel EEG to see how integrated the response is (low in deep sleep and high in awake states).
- The theory also makes predictions about machine consciousness that are fundamentally different from the predictions of functionalism. Functionalism states that if you emulate the functions of a system (including organisms), for instance in a computer simulation, that you will also replicate all of the system’s properties.
- IIT says that consciousness is not about functional identity but cause-effect power. The underlying physical mechanism determines consciousness; it cannot be determined by a system’s resultant actions or behaviors. The physics of the brain must be replicated, not emulated, for consciousness to arise.